Numerous vehicle safety systems have been developed which incorporate a baglike confinement having a collapsed inoperative condition and an expanded operative condition for permitting protection of a vehicle occupant during a collision. Most of these known safety systems include a fluid supply device which is located externally of the confinement and comprises a reservoir containing therein a compressed gas which is adapted to be supplied to the confinement in response to the sensing of a collision condition. These known systems often provide an explosively actuated valve for controlling flow of compressed gas from the reservoir into the confinement. While numerous systems of this type have been proposed, nevertheless the problem of controlling the flow of fluid into the confinement so as to result in proper inflation thereof has continued to exist. Controlling of the flow of fluid into the confinement during inflation thereof is critical since, as is well known, the flow must be sufficiently rapid to result in inflation within a sufficiently short period of time to properly protect the occupant. At the same time, the flow cannot be of such uncontrolled magnitude as to cause injury to the occupant due to the actual inflation of the confinement by itself.
Furthermore, uncontrolled high-pressure fluid flow can cause unacceptably high noise levels, which can result in damage to the occupants hearing. While many of the problems associated with controlling the flow into the confinement have been at least partially resolved when considering adult occupants, nevertheless attempting to provide for properly controlled inflation of the confinement when the vehicle occupant is a child has continued to present a problem.
The problem of safe deployment of an inflatable confinement is especially complex when the vehicle occupant is a child since, as is well known, the position and location of a child within the passenger compartment of the vehicle is totally unpredictable. In fact, it is a fairly common practice of children to stand directly adjacent the dashboard of the vehicle, or directly behind the front seat of the vehicle. Since an inflatable cushion is normally deployed from a position located either on the dashboard or on the back of the front seat, the rapid deployment of a safety cushion can obviously be extremely harmful and injurious to a child who happens to be standing directly in front of the confinement storage position prior to inflation thereof.
It has been determined that, of all the variables affecting inflation of a confinement and the injurious effect of same on an out-of-position child, the flow rate of gas into the confinement is one of the most critical factors. Accordingly, the present invention relates to an improved flow control device designed specifically to control and regulate the gas flow into a confinement to at least minimize the injurious effects of confinement inflation on an out-of-position child.
Thus, it is an object of the present invention to provide:
1. A flow control device, as aforesaid, which utilizes a variable orifice flow control valve for controlling flow of fluid into the confinement.
2. A flow control device, as aforesaid, wherein the flow control valve results in an optimum gas fill rate of the confinement while operating reliably over the temperature and pressure range encountered in service.
3. A flow control device, as aforesaid, which can be positioned externally of the fluid storage reservoir and is effective for substantially reducing the level of sound generated during inflation without increasing inflation time, and wherein the flow control device lowers diffuser pressures into the range whereby plastic or fabric diffusers are feasible.
4. A flow control device, as aforesaid, which also permits overfill of the confinement to be controlled.
5. A flow control device, as aforesaid, which can be positioned internally of the fluid storage reservoir while still effectively controlling flow therefrom into the confinement.
6. A flow control device, as aforesaid, which includes a movable valve member which is progressively moved to increase the orifice of the valve until a maximum flow area is achieved, thereby controlling the initial inflation of the confinement.
7. A flow control device, as aforesaid, wherein the movement of the valve member is at least in part controlled by the application of pressure fluid to a portion of the valve member for at least partially balancing the pressures imposed thereon.
8. A flow control device, as aforesaid, wherein movement of the valve member is controlled by a frictional retarding force created by the flowing pressure fluid.
Other objects and purposes of the present invention will be apparent to persons acquainted with devices of this type upon reading the following specification and inspecting the accompanying drawings.